Pour equal amounts of epoxy resin and epoxy hardener into a plastic container. Do not make more epoxy than you can apply in 15 minutes, as epoxy quickly starts to harden after mixing the two parts.
Add just a couple of drops of all-purpose tint, using the desired tint color. Use two or more tints to create a new color not available in a single tube.
Note the amount of epoxy used and the number of drops added so you know how much to use in a subsequent batch to achieve a matching tine.
Stir the resin, hardener and tint. Examine the tint or test a dab on an inconspicuous area of the shower. Add a few more drops of tint if necessary to enrich the glaze color.